I didn't use any backing. It is Like industrial carpet. I measured it out, cut couple small holes for the window winder and door handle and glued er up. Its not JDM but it came ot pretty good IMHO. Just gotta work with what you got sometimes

Unless you really want to be authentic, you can make the hood pads, or bumper pads, etc from sections of old tire. Somewhere on here is a thread where a guy cut sections out using a hole saw. A band saw would let you cut them to fit. Just a thought.